import javax.swing.plaf.basic.BasicLookAndFeel;
import java.util.Scanner;

public class Hello {
    public static void main9(String[] args) {
        int a = 10;
        System.out.println(a);
    }
    public static void main8(String[] args) {
        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        int b=sc.nextInt();
        int min=a>b?b:a;
        int ret=0;
        for(int i=1;i<=min;i++)
        {
            if((double)a%i==0&&(double)b%i==0){
                ret=i;
            }
        }
        System.out.println("最大公约数为"+ret);

    }
    public static void main7(String[] args) {

        Scanner sc=new Scanner(System.in);
        int n= sc.nextInt();
        int count=0;
        while(true)
        {
            n=n&(n-1);
            count++;
            if(n==0){
                break;
            }

        }

        System.out.println("1的个数为"+count);



    }
    public static void main6(String[] args) {
        double sum=0;
        for(int i=1;i<100;i++)
        {
            double ret=1.0/i;
          sum+=ret;
        }

        System.out.println(sum);
    }
    public static void main5(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        if(n<100){
            System.out.println("输入错误");
        }else{

            for(int i=100;i<n;i++){
                int d1=i%10;
                int d2=i/10%10;
                int d3=i/100%10;
                int sum=d1*d1*d1+d2*d2*d2+d3*d3*d3;
                if(sum==i){
                    System.out.println(i);
                }


            }
        }



    }
    public static void main4(String[] args) {


// 注意类名必须为 Main, 不要有任何 package xxx 信息


                Scanner in = new Scanner(System.in);
                // 注意 hasNext 和 hasNextLine 的区别
                while (in.hasNextInt()) { // 注意 while 处理多个 case
                    int n = in.nextInt();
                    for(int i=0;i<n;i++){
                        for(int j=0;j<n;j++){

                            if(i==j||i==n-1-j)
                            {
                                System.out.print('*');
                            }else{

                                System.out.print(' ');
                            }
                        }
                        System.out.print('\n');

                    }





        }


    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int i = 0;
        for (i = 2; i < n / 2; i++) {

            if (n % i == 0) {
                System.out.println("不是素数");
                break;

            }


        }
        if (i >= n / 2) {
            System.out.println("是素数");
        }
    }
    public static void main1(String[] args) {
        int count=0;
        for(int i=1;i<100;i++){

            if(i%10==9){

                count++;

            }
            if(i/10==9){
                count++;
            }

        }
        System.out.println("出现9的次数为"+count+"次");
    }

}
